Froehlich, Andrew
CVOICE 8.0 implementing cisco unified communications voice over IP and QoS v8.0 : study guide
John Wiley & Sons, 2012
 Buku Teks SO
Lammle, Todd
CCNA: cisco certified network associate study guide
Wiley , 2011
 Buku Teks SO
Andrews, jean
A+ guide to software: managing, maintaining, and troubleshooting
Course technology cengage learning, 2013
 Buku Teks SO
Official (ISC)² guide to the ISSMP CBK
edited by Harold F. Tipton
CRC Press, 2012
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Voice over IP: systems and solutions
edited by Richard Swale
Institution of Engineering and Technology, 2008
 eBooks